Have you ever played with magnets? You might have done an experiment where you lay a magnet onto a table and place an iron nail nearby. If you push the magnet slowly toward the nail, there will come a point when the nail jumps across and sticks to the magnet. That's because magnets have something invisible that extends all around them, called a 'magnetic field'. It can cause a pushing or pulling force on other objects, even if the magnet isn't actually touching them.

The most powerful magnets in the Universe are called magnetars. These are tiny, super-compact stars, 50 times more massive than our Sun, squashed into a ball just 20 kilometers across. (That's about the size of a small city!)

Astronomers think magnetars may be created when some massive stars die in a supernova explosion. The star's gases blow out into space creating a colourful cloud like the one in this picture, called Kes 73. At the same time, the core of the star squashes down to form a magnetar.

At the center of the cosmic cloud in this photograph lies a tiny magnetar. But what this star lacks in size it makes up for in energy, shooting out powerful jets of X-rays every few seconds! You can see the X-ray jets in blue in this photograph.
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Over its decade and a half in orbit, NASA's Chandra X-ray Observatory has looked at many different objects. Some of its most spectacular images are undoubtedly of supernova remnants. Because the debris fields of exploded stars are very hot and energetic, they glow brightly in X-ray light. The supernova remnant called G299.2-2.9, or G299 for short, is no exception. This new Chandra image of G299 shows a beautiful and intricate structure in the expanding remains of the shattered star. By analyzing the details of the remnant today, astronomers can get information about the explosion that created the remnant about 4,500 years ago.
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The year of 2015 has been declared the International Year of Light, or IYL for short, by the United Nations. Organizations, institutions, and individuals involved in the science and applications of light will be joining together for this year-long celebration to help spread the word about the wonders of light.

In many ways, astronomy uses the science of light. By building telescopes that can detect light in its many forms from radio waves on one end of the "electromagnetic spectrum" to gamma rays on the other, scientists can get a better understanding of the processes at work in the Universe.

NASA's Chandra X-ray Observatory explores the Universe in X-rays, a high-energy form of light. By studying X-ray data and comparing them with observations in other types of light, scientists can develop a better understanding of objects that generate temperatures of millions of degrees and produce X-rays.

To recognize the start of IYL, the Chandra X-ray Center is releasing a collection of images that combine data from telescopes tuned to different wavelengths of light. From a distant galaxy to the relatively nearby debris field of an exploded star, these images demonstrate the myriad ways that information about the Universe is communicated to us through light.

So join us in celebrating IYL and all of the amazing things that light can do, including how it helps us understand the Universe we live in.
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In movies, heroes and villains are thrown forward after an explosion. This is because a powerful wave of energy, called a shock wave, is released. In space, the same thing happens when a star explodes in what is called a supernova explosion.

The shock wave from the supernova is absorbed by the star's outer shells of gas and dust, which escaped from the star before the explosion. It heats the gas so that it gives off X-ray radiation, which astronomers can photograph using special telescopes in space.

Astronomers took two pictures of this glowing cloud of gas and dust, which were taken about a year apart. By comparing the two X-ray photos, astronomers think that the shock wave is finally escaping from the cloud. This is the first time that astronomers have X-ray evidence for a shock wave breaking free from its gassy and dusty cocoon!
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Every year, NASA's Chandra X-ray Observatory looks at hundreds of objects throughout space to help expand our understanding of the Universe. Ultimately, these data are stored in the Chandra Data Archive, an electronic repository that provides access to these unique X-ray findings for anyone who would like to explore them. With the passing of Chandra's 15th anniversary, in operation since August 26, 1999, the archive continues to grow as each successive year adds to the enormous and invaluable dataset.

To celebrate Chandra's decade and a half in space, and to honor October as American Archive Month, a variety of objects have been selected from Chandra's archive. Each of the new images we have produced combines Chandra data with those from other telescopes. This technique of creating "multiwavelength" images allows scientists and the public to see how X-rays fit with data of other types of light, such as optical, radio, and infrared. As scientists continue to make new discoveries with the telescope, the burgeoning archive will allow us to see the high-energy Universe as only Chandra can.
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The destructive results of a powerful supernova explosion are seen in a delicate tapestry of X-ray light in this new image. The remnant is called Puppis A, which could have been witnessed on Earth about 3,700 years ago and is about 10 light years across. This image is the most complete and detailed X-ray view of Puppis A ever obtained, made by combining a mosaic of different Chandra and XMM-Newton observations. In this image, low-energy X-rays are shown in red, medium-energy X-rays are in green and high energy X-rays are colored blue.
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Earlier this year, astronomers discovered one of the closest supernovas in decades. Now, new data from NASA's Chandra X-ray Observatory has provided information on the environment of the star before it exploded, and insight into the possible cause of the explosion. On January 21, 2014, astronomers witnessed a supernova just days after it went off in the Messier 82, or M82, galaxy. Telescopes across the globe and in space turned their attention to study this newly exploded star. Astronomers quickly determined this supernova, dubbed SN 2014J, belongs to a class of explosions called "Type Ia" supernovas. These supernovas are used as cosmic distance-markers and played a key role in the discovery of the Universe's accelerated expansion, which has been attributed to the effects of dark energy.

While astronomers agree that Type Ia supernovas occur when a white dwarf star explodes, they are not sure exactly how this happens. For example, do these supernovas go off when the white dwarf pulls too much material from a companion star like the Sun, or when two white dwarf stars merge? Researchers used Chandra to look for clues. They took observations with Chandra about three weeks after 2014J and compared it with Chandra data taken prior to the explosion. They found, well, nothing.

Although it may sound counterintuitive, this non-detection of X-rays actually told astronomers quite a bit. Specifically, it showed that the environment around the star was relatively free of material before it exploded. This means that it's very unlikely that a messy transfer of material between the white dwarf and a companion star took place. Rather, whatever caused SN 2014J to explode cleared out the space around the star beforehand. This helps astronomers narrow down the possibilities and get closer to the answer of just what caused SN 2014J.
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To celebrate the 15th anniversary of NASA's Chandra X-ray Observatory, we have released four new images of supernova remnants. These show Chandra's ability to study the remains of supernova explosions, using images that are the sharpest available in X-ray astronomy. The images of the Tycho and G292.0+1.8 supernova remnants show how Chandra can trace the expanding debris of an exploded star. The images show shock waves, similar to sonic booms from a supersonic plane, that travel through space at speeds of millions of miles per hour. The images of the Crab Nebula and 3C58 show the effects of very dense, rapidly spinning neutron stars created when a massive star explodes. These neutron stars can create clouds of high-energy particles that glow brightly in X-rays. The image for G292 shows oxygen (yellow and orange), and other elements such as magnesium (green) and silicon and sulfur (blue) that were forged in the star before it exploded. For the other images, the lower energy X-rays are shown in red and green and the highest energy X-rays are shown in blue.
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In fifteen years of operation, the Chandra X-ray Observatory has given us a view of the universe that is largely hidden from telescopes sensitive only to visible light.

Chandra has captured galaxy clusters - the largest gravitationally bound objects in the universe - in the process of forming, and provided the best evidence yet that the cosmos is dominated by a mysterious substance called dark matter.

Chandra has observed gas circling near a black hole's event horizon. The atoms of this gas are doomed to destruction by the extreme gravity of the black hole.

Most of the elements necessary for life are forged inside stars and blasted into interstellar space by supernovas. Chandra has tracked these elements with unprecedented accuracy.

Young stars are crackling with X-ray flares and other energetic radiation. By monitoring clusters of young stars, Chandra can give us a sense of what our young Sun was like when life was evolving on Earth.

Chandra: Taking us on a unique voyage into the big, bad and beautiful universe.
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Supernovas are the spectacular ends to the lives of many massive stars. They are explosions that produce enormous amounts of energy and can shine as bright as an entire galaxy made up of billions of stars! These events are very important because the remains of the shattered star are hurled into space. This material goes on to form new stars, planets and moons - in fact, both you and I are made of supernova material! As these fields of leftover star material (called supernova remnants) expand, they sweep up all the material they encounter and carry it along with them.

This space photograph shows a 2200-year-old supernova remnant that is sweeping up a remarkable amount of material - enough to make 45 Suns! The blue material in the picture shows the supernova remnant, the space dust is shown in pink. The impressive amount of material swept up by this remnant may be the first clue that something special happened to this star before it exploded. Another clue is the temperature of the material, which is unusually hot and still emitting (sending out) high-energy X-rays. With 2200 years having passed since the supernova explosion, the remaining material has normally cooled much more. Unfortunately, you'll have to watch this space to find out the cause for these oddities, as scientists are still trying to figure it out themselves!
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